Hip dysplasia is a common problem in veterinary practice, accounting for up to 30% of canine orthopedic cases (Richardson D. C. “The role of nutrition in canine hip dysplasia.” Vet Clin North Am Small Anim. Pract. 1992; 22: 529-540). The frequency of the disease varies among breeds and can be as high as 70.5% in bulldogs and 48.2% in St. Bernards (Corley E. A, Keller G. G. “Hip Dysplasia: A Progress Report and Update.” Columbia, Mo.: Orthopedic Foundation of Animals 1993 (suppl)). Male and female dogs are affected with equal frequency, in contrast to the disease in humans, where 80% of cases are female (Committee on Quality Improvement, Subcommittee on Developmental Dysplasia of the Hip “Clinical Practice Guideline: Early Detection of Developmental Dysplasia of the Hip” Pediatrics (2000) 105: 896-905).
The canine coxofemoral joint is a ball and socket joint, where the femoral head meets the socket of the acetabulum. In chronic canine hip dysplasia, the joint becomes deformed where the femoral head is subluxed out of the joint resulting in significant pain, restricted range of motion, and accelerated osteoarthritic changes of the joint.
Treatment for canine hip dysplasia can include total hip replacement. Total hip replacement has become one of the most successful procedures utilized in the treatment of canine hip dysplasia, and associated disorders such as coxarthrosis; severe osteoarthritis, chronic subluxation, avascular necrosis, and fracture dislocation. The typical minimum age for total hip replacement is approximately 10 months and/or a body weight of 35 pounds, and there appears to be no upper age limit for total hip replacement (Olmstead M L. “Total hip replacement.” Vet Clin North Am Small Anim Pract 1987, 17, 943-955; Tomlinson J, McLaughlin R Jr. “Total hip replacement: The best treatment for dysplastic dogs with osteoarthrosis. Symposium on CHD: Surgical Management.” Vet Med 1996, 91, 118-124; and Olmstead M L. “Total hip replacement in the dog.” Semin Vet Med Surg (Small Anim) 1987, 2, 131-140). However, total hip replacement can lead to complications such as aseptic loosening, chronic subluxation, nerve injury, infection, fracture of the acetabulum, fracture of the femoral stem or shaft, patella luxation, pulmonary embolism and death (Konde L J, et al. “Radiographic evaluation of total hip replacement in the dog.” Vet Radiol 1982, 20, 98-106; Liska W D. “Femur fractures associated with canine total hip replacement.” Vet Surg 2004, 33, 164-172; and Montgomery R D et al. “Total hip arthroplasty for treatment of canine hip dysplasia.” Vet Clin North Am Small Anim Pract 1992, 22, 703-719).
Despite expensive screening and breeding programs, the disease continues to have a major economic and emotional impact on dog breeders and owners. Accordingly, there is a need for minimally invasive methods and devices to treat hip dysplasia and associated disorders.